Lazy cruise control?

[6.9poweredscout]

On my '91 the cruise will work, i'll have it in OD doing 65-70 and i'll turn it on, i'll feel the pedal "pull" and the truck will hold it for a bit, but any hill and it loses momentum and the cruise kicks off. if I ever so lightly hold the pedal it'll maintain speed. is there an adjustment or anything I can look for?

 

[chris142]

Mine does the same thing. You would think that the cruise would pull more than 1/4 pedal. The max I can set my cruise is about 72. Any more and I gotta step on it.

 

[The Warden]

I had something like that happen...and, it got to the point where I would have to keep light pressure on the pedal for the cruise to maintain speed...and, after 5K (mostly highway) miles or so, it failed altogether. Replaced the actuator and it was good as new

 

[6.9poweredscout]

Can you get those new?

 

[OLDBULL8]

Do you still have the vacuum reservoir (tomato juice can) that is needed for cruise control servo operation? If not enough vacuum, the cruise will kickout instead of letting the engine lug. Check your vacuum, should have 21Hg with a good pump. Could be a defective servo also.

 

[gandalf]

We have an article in the Tech Section for diagnosing Electronic Cruise Control.


I have a diagnostic for the older Vacuum Cruise Control. I'd be happy to send it to anyone. If you want a copy, PM me with an email address.

Mine, which I lifted from somewhere, is 6+ pages in M$Word. It starts out:
[h=1]"Speed Control Systems[/h]
[h=1]Description and operation[/h]
[FONT=&quot] The speed control system is composed of on-off, set-acc, coast and resume (if equipped ) switches. The system contains vacuum hoses, servo (throttle actuator) assembly, speed sensor, amplifier, check valve assembly, and depending on model and year, a clutch switch, stop light switch and/or vacuum dump valve. 1983-86 models w/resume, also use a vacuum reserve tank. ..."[/FONT]

It goes on, step by step, for 6 pages. The first step is, "Blow your horn." I recall on my '86 the cruise control and the horn were on the same relay circuit.